etrex vista hcx tripcomputer false results

[scubasteve1942]

Has gramin acknowledged that they are aware of this problem? Can this problem be fixed with and update?

Edited August 6, 2007 by scubasteve1942

[scubasteve1942]

Sorry for all the replies. I have no idea what happened.

[freeday]

Nice to hear that shaunknee has the same bug. As already mentioned in europe are also some guys who had the same result.

I already informed garmin. But i think it could be necessary that more people will mail to garmin.

 

I think a lot of people using the HCX will not see the false trip odom bcause they have no possibility of comparsion.

And who will compare the trip odom with the logged trip

... seems to be a low speed-problem.

Edited August 6, 2007 by freeday

[scubasteve1942]

So far from what I have read the issue seems to be speed related, as stated above. I think I will give garmin a call today and see if they are aware of the issue.

[Skyliner]

I too was having weird results with the track log though it still recorded accurate elapsed miles in the trip computer. Driving and riding my bike it was okay. However, walking around in the driveway it would not log the tracks - the triangle wouldn't move. Last night I updated to 2.30 which seems to have improved the sensitivity of the track log. Has anyone else noticed this change?

 

Dirk

[scubasteve1942]

This thread is really leading me towards buying a GPSMap60 Csx instead of the Vista Hcx. Any word from garmin yet?

[captain454]

one thing I've done is change the track log to manual distance logging, and set the distance between breadcrumbs to 0.00 miles. Sure, it takes up a lot of space, but you can literally see every step you take, and if you use one of the 2GB microSD cards, you'll never run out of space anyway.

[freeday]

I too was having weird results with the track log though it still recorded accurate elapsed miles in the trip computer. Driving and riding my bike it was okay. However, walking around in the driveway it would not log the tracks - the triangle wouldn't move. Last night I updated to 2.30 which seems to have improved the sensitivity of the track log. Has anyone else noticed this change?

 

Dirk

My latest test was already with v2.30

please look at post #39

[hedtjarn]

I think a lot of people using the HCX will not see the false trip odom bcause they have no possibility of comparsion. And who will compare the trip odom with the logged trip

... seems to be a low speed-problem.

Right on the spot you are! My Vista HCx will arrive this week and had you guys not compared it with other units, I would not have known about this issue =) Let´s hope Garmin fix this for some later firmware upgrade.

 

If I understand correctly, I can extract the logged trip and let my laptop show the length of it and thus compare that number to the odom? I will look into this when [Gollum mode]my precioussssssssssss[/Gollum mode] arrives.

Edited August 7, 2007 by hedtjarn

[yeeoldcacher]

This doesn't only pertain to the new high sensitivity etrex units, it happens with the 60 and 76 x units as well. It seems it is directly related to the high sensitivity receivers as a whole.

 

http://forums.Groundspeak.com/GC/index.php...ometer+gpsmap60

 

This thread is really leading me towards buying a GPSMap60 Csx instead of the Vista Hcx. Any word from garmin yet?

[scubasteve1942]

Thanks for the link yeeoldcacher. I did a search but never came across that thread. It was very helpful. I think I will reconsider and most likley go with the vista hcx as it is a little cheaper. Thanks again.

[Androo]

I can confirm this behavior. I took the Vista HCx on a 6.5 mile hike in the mountains this weekend with moderately heavy tree cover. The trip odometer claimed that we had only covered something like 3 miles when we finished, but the tracklog was reported as exactly the 6.5 miles I was expecting. The trip computer reported that we were stopped for over two hours of the four hours it took us to complete the hike, when we were actually stopped for a total of about 15 minutes.

[freeday]

I can confirm this behavior. I took the Vista HCx on a 6.5 mile hike in the mountains this weekend with moderately heavy tree cover. The trip odometer claimed that we had only covered something like 3 miles when we finished, but the tracklog was reported as exactly the 6.5 miles I was expecting. The trip computer reported that we were stopped for over two hours of the four hours it took us to complete the hike, when we were actually stopped for a total of about 15 minutes.

I hope the weather forecast was more accurate than the trip odometer

[nivko]

Does anyone know if this trip odometer bug applies to Etrex LEGEND HCx as well?

[shaunknee]

Does anyone know if this trip odometer bug applies to Etrex LEGEND HCx as well?

 

Yes I am having this problem with the Legend and not the Vista. I compared a 100 mile drive yesterday. A discrepancy popped up immediately between my Legend C and HCX of 10 meters (30-40 feet) and then the distances in the trip page remained exactly the same for the entire trip. The Legend C was 10 meters longer. The issue is low speed related on my HCX.

[liamblake]

...

As I understand how these things work, the gpx file is getting its trip data from map data. In other words, its calculating distance using the long/lat of points A and B as found on the map loaded into your unit.

...

.gpx-trip-length is always the same in Mapsource. Equal if no map is loaded in MS or a (routable) Map is loaded.

 

I got the same results today. I was out in Lake Ontario assisting a swim marshal. The swimmers covered 17.5 km, but the trip odom measured 14.7km. The track log shows the correct distance. The speed and moving time didn’t seem very accurate either on the trip page. We were moving about 3km/hr most of the way, just like a slow walk.

 

Interesting. I presume the 17.5mi was measured independently of gps. I wonder if its the low speed that's creating the error. All units will have less accuracy as distance/time gets very small. Maybe the HCx is not so accurate at slow speeds?

 

I compared it to a Legend CX on the Rescue boat we were working off. His odometer matched my track measurements. Several times the non H was showing speeds where mine was showing zero. This caused the discrepancy in "moving time" between the gpsr's

 

I saw similar results with my Rino 530HCx today. I walked about two miles, half in open skies and the other half through thick tree cover. The Mapsource track log shows I walked 2.1 miles. The trip odom shows 1.94 miles. I did not lose signal at all during the walk. When I was walking under the thick trees, however, the stopped time increased. When I got back under open sky, the stopped time stopped increasing. I did not stop at all during the 40 minute trip, yet the the stopped time is almost 7 minutes.

[scubasteve1942]

This is a real bummer. I wanted to buy the vista HCX with its primary use for biking. If the trip odometer is not accurate im not so sure this is the unit for me.

 

Ditto.

 

What I want to see someone do is take their new H series unit out for a bike ride or walk. Stop for like 15 minutes, then finish the walk or ride. Then look at the trip computer screen for total time, moving time, and stopped time. If the stopped time is 15 minutes or around that, it isn't a problem. If it shows zero stopped time, it's a problem. I know on my unit, Legend Cx, if the Marine setting for Speed Filter is not set to AUTO, the unit won't calcuate any stopped time, it will have the same figure for moving time and total time. For a bicyclist like myself, that's critical information because it screws up the moving average MPH.

 

Hey I got my vista Hcx today and did this test for you. I was for the most part under clear sky, but some spots were covered by trees. I rode 5 miles stopped for 10 min and rode back. Stopped time was exactly 10 min. The trip odometer was 10 miles and matched the mapsource track log.

[freeday]

 

Hey I got my vista Hcx today and did this test for you. I was for the most part under clear sky, but some spots were covered by trees. I rode 5 miles stopped for 10 min and rode back. Stopped time was exactly 10 min. The trip odometer was 10 miles and matched the mapsource track log.

you rode

by bicycle, motorbike,...?

What was your average speed?

Did you also try it by walking or low speed?

As already mentioned it only occurs by using low speed (less than 10 km/h, better less than 5 km/h)

On using higher speed it works perfect.

[scubasteve1942]

I was on a bike. average speed 11 mph. lowest speed I got to was 2.3mph while aproaching intersections. I also tried walking and it was fine. But like I said earlier most of the time I was not under any trees.

Edited August 10, 2007 by scubasteve1942

[freeday]

GPS Chipset Type B (Region File) software version 2.30 as of August 1, 2007

 

Maybe a new GPS-FW for H-series?

http://www8.garmin.com/support/download_details.jsp?id=3621

http://www.gpsinformation.org/allory/new.htm

 

does anyone have more information?

[SergZak]

GPS Chipset Type B (Region File) software version 2.30 as of August 1, 2007

 

Maybe a new GPS-FW for H-series?

http://www8.garmin.com/support/download_details.jsp?id=3621

http://www.gpsinformation.org/allory/new.htm

 

does anyone have more information?

 

I tried updating to this when it was released up until a few days ago but WebUpdater never found this update file for the Vista HCx.

[Stive Gonzales]

I just did my first walk out with my new HCx today and back at my laptop now I'm seeing the same thing.

 

Trip Distance 7.67km

Track Length 8.8km

 

The unit spent quite a lot of time showing my speed as 0kph - especially on steep climbs - and as far as I'm concerned that's all that's required to explain the discrepancy.

 

I notice that the "Speed Filter" that was on my Vista Cx (R.I.P.) is gone from the Marine tab of the Map setup screen on the HCx. It would appear that the HCx algorithm for determining whether you're moving or not isn't as effective or reliable as that in the older units.

 

Having said that; I was under the impression that speed could be calculated without position measurement...

"GPS receivers typically calculate velocity by measuring the frequency shift (Doppler shift) of the GPS D-band carrier(s)"

... so there's no excuse for a GPSr being confused over whether it's moving or not unless your're cutting corners and costs.

 

Fix it Garmin. Thanks.

[dogwalkers2]

 

Having said that; I was under the impression that speed could be calculated without position measurement...

"GPS receivers typically calculate velocity by measuring the frequency shift (Doppler shift) of the GPS D-band carrier(s)"

... so there's no excuse for a GPSr being confused over whether it's moving or not unless your're cutting corners and costs.

 

Fix it Garmin. Thanks.

Yes, they measure frequency shift; however, this measurement is still subject to errors, just like position is subject to error. The errors are increased/more likely with multi-path and weaker signals, hence the problem "under tree cover" as noted elsewhere. Furthermore, multipath signals are more susceptible to fading, so when you are already receiving a weak signal with a high sensitivity reciever, errors are introduced, where in previous models of GPS (i.e. "Old Blue" Legend) the signal was just lost and you had no position, no velocity, nothing...I like having at least some information.

 

So, yes it is cutting costs. A GPS receiver can be designed to minimize the errors (including such techniques as filtering with inertial navigation systems, etc.), but I like my GPS for under $300 (at least affordable), rather than significantly more expensive and unaffordable.

[Bite_Me]

I recently did a hike that started with a 20% or higher grade. I reset my 60csx and immediately started hiking. I'm going rather slow, <1 mph, up this steep grade. After half an hour I stop for a drink. The trip computer showed I as moving for 10 minutes and was stopped for 20 minutes. The funny thing is my legs and lungs were telling me I was moving for the whole half hour. So my trip computer recorded only 33% of the time I was on the move. Later on this hike near the summit I came upon a couple and they asked me "how much further to the top?" So I grabbed my gps, went to the track screen, saved the entire track, brought up the saved track to see how far we were from the trailhead. Since I knew how long the hike was I was able to answer their question. It's too bad, but the trip computer is not as accurate as the track log when hiking at "slow" speeds. The trip computer is much better when hiking back down hill at higher speeds.

 

It seems to me when you are moving at a slow speed this movement is considered by the gps as drift, the movement you see on your screen when in fact you are stationary. So Garmin has to determine what movement is drift and leave it out of the trip computer and what movement it should include into the trip computer. Perhaps add an option where "all" movement is added to the trip computer and thus there would be no stoppage time and when a person is stationary the gps drift is added to the trip computer. So the trip computer would error on the high side versus the track log. What I would like is an option where the trip computer simply shows the length of the active track log.

[Rhialto]

Just wanted an update on this. It must have been submitted to Garmin by now but do they have confirmed there is a problem and that a fix is coming?

 

Or we are only discussing it?

[captain454]

but I like my GPS for under $300 (at least affordable), rather than significantly more expensive and unaffordable.

 

Well I don't. The price is the last thing I'm going to worry about, especially with something I use this much. I would be more than happy to pay well over $1000 dollars for a GPS if it was the same size/shape as the eTrex but had greatly improved features. Just point me in the right direction...

[dogwalkers2]

but I like my GPS for under $300 (at least affordable), rather than significantly more expensive and unaffordable.

 

Well I don't. The price is the last thing I'm going to worry about, especially with something I use this much. I would be more than happy to pay well over $1000 dollars for a GPS if it was the same size/shape as the eTrex but had greatly improved features. Just point me in the right direction...

Well, I'd say you are not in the market Garmin is aiming for in producing their "recreational" GPSs such as the eTrex.

 

It appears you may have to wait a little to get what you want. See http://forums.gpsworld.com/showthread.php?t=33 where it states

The solution is simple, in concept: use an inertial measurement unit (IMU) to measure receiver motion and compensate for motion during integration. This technique, known as Ultra-Tight (or Deep) GPS/INS integration, is currently a hot topic of research, with the major unresolved issues being the cost and size of IMUs with sufficient accuracy for the task. Ongoing developments in IMU technology are likely to make UT integration a viable technique for devices such as cellular phones in the near future.

This brief paper/article was written within the last couple of months and is discussing related issues.

 

To add to the complexity of the topic and solution, I believe Bite_Me was correct when he said:

It seems to me when you are moving at a slow speed this movement is considered by the gps as drift, the movement you see on your screen when in fact you are stationary. So Garmin has to determine what movement is drift and leave it out of the trip computer and what movement it should include into the trip computer. Perhaps add an option where "all" movement is added to the trip computer and thus there would be no stoppage time and when a person is stationary the gps drift is added to the trip computer. So the trip computer would error on the high side versus the track log. What I would like is an option where the trip computer simply shows the length of the active track log.

But then there would be complaints that it's not accurate because it would be showing motion when you are standing still. By the way, the length of the active track log is often in error when you are standing still as it includes any motion because of the "drift."

 

There's got to be some compromises, especially when dealing with a consumer product meant for the masses. There's a reason surveying GPS systems are so expensive...

[freeday]

...

Thank you for contacting Garmin International.

 

I will pass this information on to the appropriate department. Thank

you.

...

 

I do not know if they will fix it or are able to do so.

[Stive Gonzales]

I'd just like the HCx to be as reliable, with respect to whether I'm moving or not, as my Cx was.

 

Unfortunately, it isn't. They both cost the same, but the older model doesn't have an instantaneous speed readout that fluctuates constantly between zero and some random approximation of speed.

 

I don't really care how they did it with the Cx. Perhaps it was simply averaging over several consecutive measurements. Whatever it was; it seemed to work. The moving vs. stopped times made sense and so did the speed, even when walking.

[Smac999]

have other people had huge problems with this? the distance beging way off in the trip meter. and the moving and stoped times being totaly wrong?